1. Field of the Invention
The present invention relates to a switching regulator, and particularly to protection circuits of a switching regulator.
2. Background Art
A switching regulator has been used as a voltage supply source for various electronic apparatuses. Thus, various protection functions have been becoming important functions to ensure the safety of the electronic apparatuses.
FIG. 2 illustrates one example of a circuit diagram of a related art switching regulator. The related art switching regulator 200 is equipped with a feedback resistor 6, a reference voltage circuit 12, a comparison circuit 10, an R-S flip-flop circuit 13, an on-time control circuit 11, an output control circuit 15, driver circuits 16 and 17, power FETs 2 and 4, an inductor 3, and a capacitor 5. Further, the related art switching regulator 200 is equipped with a power supply voltage monitoring circuit 30, an overheat protection circuit 40, and a control circuit 14 as protection circuits.
The related art switching regulator 200 is equipped with various protection circuits such as the power supply voltage monitoring circuit 30 and the overheat protection circuit 40. Detected signals outputted respectively therefrom are inputted to the control circuit 14. In response to the detected signals of the various protection circuits, the control circuit 14 controls the comparison circuit 10 and the output control circuit 15 to protect the circuits from abnormal states.
The power supply voltage monitoring circuit 30 is equipped with a comparison circuit 31 which detects a power supply voltage (refer to, for example, Patent Document 1). The overheat protection circuit 40 is equipped with a comparison circuit 41 which detects a temperature.